im ‧ pe ‧ ri ‧ al /ɪmˈpɪəriəl $ -ˈpɪr-/ BrE AmE adjective [only before noun]
[ Date: 1300-1400 ; Language: French ; Origin: Late Latin imperialis , from Latin imperium 'command, empire' ]
1 . relating to an ↑ empire or to the person who rules it:
Britain’s imperial expansion in the 19th century
2 . relating to the system of weights and measurements based on pounds, ↑ inch es , miles etc